An ozone water generator conventionally includes an ozone generator and a gas-liquid mixer, and is operated to mix ozone gas generated in the ozone generator with a liquid such as water to generate ozone water. However, since ozone gas has low solubility to water, most of ozone gas generated in the ozone generator cannot be completely dissolved in water and discharged.
Thus, in order to increase the use efficiency of ozone gas, an ozone water generation apparatus collecting and recycling the undissolved and discharged ozone gas is disclosed. For example, Japanese Patent Laying-Open No. 02-207892 (PTD 1) discloses the invention including an ozone generator; a gas-liquid mixer; a hermetically-sealed tank having a function of separating a gas-liquid mixture into gas and a liquid; and a gas return path connecting the hermetically-sealed tank and the ozone generator. Ozone gas separated by the hermetically-sealed tank is supplied to the ozone generator through the gas return path. Thus, it becomes possible to recycle undissolved ozone gas contained in exhaust gas.
Furthermore, in the above-described configuration, when generation of ozone water is continued for a certain period of time, gas dissolves in water, which is then caused to flow to the outside of the ozone water generation apparatus. Consequently, the volume of the gas within the hermetically-sealed tank decreases. Thus, there are provided with a level switch capable of detecting the decreased amount of gas within the hermetically-sealed tank and a control circuit controlling supply of oxygen from an oxygen cylinder to the ozone generator, thereby allowing replenishment of oxygen, so that ozone water can be continuously generated with stability.